292 ZOO-GEOGRAPHICAL DISTRIBUTION [CH. 



of Gomphini, (iii) strong development of the Macromiini, (iv) the 

 development of the tribe Teinobasini, including some rather large 

 species which suggest the beginnings of a hypertrophied or 

 "gerontic" group. 



The Australian Region. 



Besides the continent of Australia, Tasmania, and the isolated 

 province of New Zealand with its adjacent islands, this region 

 includes the immense Papuan province, which embraces all the 

 islands lying to the east of Wallace's Line. Chief amongst these 

 are Celebes (at least the highlands of this island), Timor, New 

 Guinea, the Solomons, the New Hebrides, New Caledonia^ and 

 Fiji. The latter must be included, not only on account of the 

 recent geological demonstration of its continental origin, but also 

 because of the presence of three essentially continental genera, 

 viz. Synthemis, Hypothemis and Nesobasis. 



The fauna of the Papuan portion of the region is so different 

 from that of the rest that one may well question the wisdom of 

 including the two within one region. In the Odonata, at any 

 rate, the Papuan fauna, so far as we know it at present, has closer 

 affinities with the Oriental than with the Australian fauna proper. 

 It is advisable, however, not to proceed to any definite decision 

 yet, because the highlands of Papua are not yet explored. It is 

 just at these higher levels that the Australian character of the 

 fauna may be expected to make itself felt, whereas the Oriental 

 portion is flagrantly noticeable along the overheated coast-line, 

 as it is also in North Queensland. Within the last few years such 

 essentially Australian genera as Synthemis and Diphlebia have 

 been found in Papua, and we may confidently look for more. 



Taking the region as a whole, out of 110 genera known, 61, or 

 55 per cent., are peculiar to or entogenic in it 1 . This low proportion 

 is wholly due to the immense irruption of Oriental forms into 

 the tropical part of the region. This is more fully dealt with in 

 the section on Ectogenic Fauna. 



The autochthonous Odonate fauna of the Australian region 

 consists chiefly of a very rich archaic complex of forms not to be 

 paralleled in any other region. Besides the occurrence of Petalura, 

 1 See foot-note on p. 286. 



